Thin films of nickel, nickel alloys such as AuGeNi and NiP2, nickel silicides, nickel gallides or nickel aluminides are widely used for the manufacture of semiconductor devices, nano-structures, hydrogen storage alloys and microelectromechanical actuators.
There have been reported studies of preparing such nickel-containing films by metal organic chemical vapor deposition (MOCVD) using nickel tetracarbonyl [Ni(CO)4]; nickelocene compounds such as bis(cyclopentadienyl) nickel [Ni(η5-C5H5)2] and bis(methylcyclopentadienyl) nickel [Ni(η5-CH3C5H4)2]; nickel β-diketonate compounds such as Ni(acac)2 (acac=2,4-pentanedionato) and Ni(hfac)2 (hfac=1,1,1,5,5,5-hexafluoro-2,4-pentanedionato). In addition, there have been disclosed reports regarding an organonickel precursor containing two β-ketoimine or aminoalkoxide ligands with nitrogen donor moieties which are capable of forming dative bonds with nickel [J. D. Martin, P. Hogan, K. A. Abboud, K.-H. Dahmen, Chem. Mater., 1998, 10, 2525; and L. G. Hubert-Pfalzgraf, H. Guillon, Appl. Organomet. Chem., 1998, 12, 221].
However, Ni(CO)4 is very toxic while the nickel β-ketoimine compound has relatively low volatility, and the above conventional precursors are known to give nickel thin films containing carbon and oxygen contaminants.